59
Febr. 28. 1666.
The formerly produced circular pendul
u designed for
an equal motion w
th vnequal weights, being again
spoken of,
the President affirm'd,
tht tho
the Author
had demonstrated,
tht the Bullet of
the arc. pendul
u, if it
can be alwayes kept rising or falling in a parabola, will
keep its circular motion in
the same time; yet he hath
not demonstrated, that
the diameter of
the parabola
from
the point of contact in the curve to
thevertex
of
the diameter, is equal to
tht portion of
the curve,
from
the s
d point of contact to
the vertex of
the same
curve,
plus half
the latis rectum or plus double
the focus of
the parabola.
Ref: CELL/RS/HF_061 © Centre for Editing Lives and Letters
